This article assesses the relationship between the Pro Archia text as it was transmitted by the famous (but lost) witness that Petrarch discovered in 1333 in Liège (π), and the other major witnesses on which editors have hitherto been relying. In a new bipartite stemma, the particular readings of G (Brussels, Koninklijke Bibliotheek van België, 5348-5352), a twelfth-century manuscript that has generally been considered the codex optimus, have to give way to a more balanced approach, weighing up the consensus of G and two other primitive witnesses against the reconstruction of Petrarch’s π.